Answer
$xy=-y^3+c$
Work Step by Step
The standard form of the given equation is:
$x dy+y dx=-3y^2 dy$ ....(1)
In order to determine the general solution, multiply equation (1) with the integrating factor and integrate both sides.
$\int [xy]' =\int -3y^2 dy$
Thus, we have
$xy=-y^3+c$